COLLECTIONS AND SPAWNING OF ANIMALS
We collected mussel broodstock from high and low density sites within each of three locations in Port Phillip Bay, Victoria, Australia during the May winter spawning season. These included Williamstown (-37.861695°, 144.912751°), Geelong (-38.148770°, 144.390864°) and Portarlington (-38.111790°, 144.659556°). Mussels were transported to the Victorian Marine Science Consortium research laboratories at Queenscliff and held in flow-through tanks at ambient temperature (16 °C). All animals were cleaned of epiphytes and other debris and used for spawning on the day of collection using the approach of Pettersen et al. (2010).